### MEMORANDUM

TO: Lisa Biddle, EPA

Karen Milam, EPA

FROM: Brent Ruminski, ERG

Sarah Yates, ERG

DATE: June 7 , 2016

SUBJECT: Analysis of Active Undergrou nd Injection for Disposal Wells ( DCN

SGE01187 )

This memorandum describes data and methods that ERG used to compile information on Underground injection wells and their relationship to the UOG industry for the Technical Development Document for Proposed Effluent Limitations Guideli nes and Standards for Oil and
Gas Extraction (TDD) (DCN SGE0 1188 ) . Specifically, this memorandum focuses on the tables and figures included in Chapter D.5 of the TDD, as listed in Table 1. TDD Tables and figures
that are not listed in Table 1 either did no t require calculations and/or analyses by ERG or are described in separate, supporting memoranda. The Crosswalk Memorandum between Proposed and Final Technical Development Document for Effluent Limitations Guidelines and Standards for Oil and Gas Extractio n: Tables and Figures (DCN SGE01334) contains a crosswalk of all

ta bles and figures in the TDD. Appendix F of the TDD contains the name of the relevant supporting memorandum for each TDD table and figure , where applicable. This memorandum is organized into the following sections:

 Section 1.0 d escribes underground injection well background ;

 Section 2.0 describes the general methodology that ERG used to tabulate the data
in Table D

- 2 and Table D

- 3 in the TDD (Chapter D, Section D.2);

 Section 3.0 describes the results of the analysis;

 Section 4.0 describes data quality and implications of key assumptions;

 Section 5.0 describes the quality assurance (QA) procedures that were followed throughout the analysis ; and

 Section 6.0 lists all of the da ta sources used in the analysis

.

For those figures/tables ERG generated specifically for this memorandum, the underlying data and analysis are contained in:

 Attachment 1 cont ains the results of the analysis (DCN SGE01187.A01).

For definitions of common terms used throughout the TDD, the supporting memoranda, and memoranda attachments, please refer to the Glossary in the introduction of the TDD.Analysis of Active Underground Injection for Disposal Wells Memorandum

June 7 , 2016 Page 2

1.0 U NDERGROUND I NJECTION W ELL B ACK GROUND

An i njection well is a device that places fluid deep underground into porous rock
formations (e.g., sandstone, limestone ) or into or below the shallow soil layer. In its underground injection well control (UIC) program codified in 40 CFR Parts 144 to 148, EPA established six
classes of underground injection wells. These classes and their relationship to the unconventional oil and gas (UOG) industry are described in Section D.2 of the TDD. C lass II wells are used to inject fluids associated with oil and natural gas production. The three types of Class II wells
include :

 Hydrocarbon storage wells ;

 E nhanced recovery wells ; and

 D isposal wells

.

Only enhanced recovery and disposal Class II wells are used to inject water. The use of

e nhanced recovery wells involves the inject ion of produced water, brine, salt water , water, steam, polymers, or carbon dioxide into oil

- bearing formations to recover re sidual oil and

— in some limited applications

— natural gas. 1 I njected fluid can move through permeable formation s to decrease the viscosity or displace small amounts of extractable oil and gas, which then becomes
less resistan t to flow and more available for production

. In a typical enhanced recovery project, a single Class II enhanced recovery injection well is surrounded by multiple oil and gas production
wells. These p roduction wells bring oil and gas to the surface , often with large volumes of produced wat er (brine) from the formation ( DCN SGE00132 ) . Many enhanced recovery projects consist of a closed loop system in which produced water from the production wells is disposed of by injection into the adjacent Class II enhance d recovery well ( DCN SGE00613 ; DCN SGE00623; DCN SGE00132 )

. According to communication with industry, t his configuration is not possible in unconventional oil and gas formations because injected fluids cannot readily flow through the low permeability formation ( DCN SGE00613 )

.

The use of Class II disposal wells involves the inject ion of wastewater associated with oil and gas extraction for permanent disposal

.
One option for managing oil and gas extraction wastewater is transport to and injection
into a disposal well (DCN SGE001 32)

. Class II disposal wells can dispose of fluids that are brought to the surface in connection with oil and gas production (e.g., conventional, CBM, UOG) and may be comingled with wastewater from gas plants

, which are an integ r al part of production opera tions. T he leading method of UOG extraction wastewater management throughout the U.S. is injection into a Class II disposal well ( DCN SGE001179 ). Furthermore, available literature and communication with industry indicates that UOG operators primarily use Class II disposal wells and typically do not use Class II enhanced recovery wells ( DCN
SGE00 635 ; DCN SGE00276; DCN SGE00625 )

.

1 The injection of fluids for hydraulic fracturing is also a form of enhanced recovery. See Legal Environmental Assistance Foundation v. EPA, 276 F.3d 1253 (11 th Cir. 2001). However, Congress amended the Safe Drinking Water Act to exempt hydraulic fracturing (except where diesel fuels are used) from regulation under the UIC

program ( SDWA section 1421(d)(1) )

. Because there are currently no Class II permits for hydraulic fracturing activities, ERG did not consider wells that have been hydraulic ally fractured within the context of this
memorandum.Analysis of Active Underground Injection for Disposal Wells Memorandum

June 7 , 2016 Page 3

2.0 G ENERAL M ETHODOLOGY

Table D

- 2 in the TDD ( DCN SGE01188 ) contains three types of data related to injection for disposal wells

, on a state

- by

- state basis :

 Number of Active Disposal Wells

 Average Disposal Rate Per Well (gpd/well)

 State Disposal Rate (MGD)

ERG tabulat ed the number of active disposal wells and disposal rates because both of these
parameters are needed to describe the availability of disposal wells. For example, two states ( A and B) may have the same number of disposal wells

, but if the average disposal rate per well 2 in
state A is much less than th at in state B, the total capacity of injection for disposal in state A will
be less than state B

. The following three subsections describe how ERG calculated and/or tabulated these three types of data for each state. Attachment 1 ( DCN SGE01187 .A 0 1) contains
the calculations and detailed documentation on a state

- by

- state basis

. ERG made several assumptions throughout this analysis in order to present available data in a meaningful way for the TDD. Potential implications of these assumptions are described in Section 4.0

.

2.1 Number of Active Disposal Wells

The Well Count Documentation tab in Attachment 1 ( DCN SGE01187 .A 0 1 ) documents
how ERG tabulated active Class II disposal wells on a state

- by

- state basis. For each state, this tab
includes :

 N umber of active disposal wells (column G ) ;

 P rimary reference for well data ( column B, “Agency/Organization” ) ;

 Source for the active well count ( column C, “DCN for Well Data” ) ;

 Type of data source for the active well count ( column D, “ Type o f Data Source ” ) ;

 D ate that the data source was accessed and last updated (columns E and F, “Date ERG Downloaded” and “Date of Last Data Update”);

 S ource of the data dictionary where relevant that was used to identify the meaning
of each field in the raw data file (column H, “Data Dictionary Source”) ; and

 H ow ERG tabulate d the number of active disposal wells using the data source (column I, “Filters to Tabulate Active Disposal Wells”).

Table 1 lists the four types of data sources ERG used to tabulate the active number of disposal wells by state . The order of the sources in Table 1 follows the general methodology
ERG used to determine the number of disposal wells by state (explained in #1 through #3 below)

. S ee the Well Count Documentation tab in Attachment 1 ( DCN SGE01187 .A 0 1 ) for a description of the state

- specific methodology

.

1. F or states where EPA maintains primary enforcement authority, ERG used data reported by EPA’s Office of Gr ound Water and Drinking Water (DCN SGE01012) titled Class II Disposal Inventory in EPA Direct Implementation Progr ams

.

2 Reasons for low disposal rates can be due to chara cteristics of the geology or permit restrictions.Analysis of Active Underground Injection for Disposal Wells Memorandum

June 7 , 2016 Page 4

2. F or states that have zero or minimal oil and gas production, ERG referenced a

table published by EPA titled UIC Inventory by State

– 2013 (DCN SGE0 1271 )

. Most of these states have no active disposal wells.

3. For the remaining states, ERG searched for databases published by state oil and

gas agencies. ERG conducted these searches in 2014, at which time many state databases contained well data for 2013 or 2014 . ERG generally used the state oil and gas database if the data was last updated in 2013 or more recently . For states where the databases were last updated in 2012 or earlier , ERG instead referenced published reports th at referenced state agency oil and g as databases

.

Table 1 . Summary of Data Sources for Active Disposal Well Counts

Type of Data Source Data Year Number
of States States

EPA OGWDW ’s Class II Disposal Inventory in EPA Direct Implementation Programs (DCN SGE01012) 2014 11 AZ, FL, HI, IA, KY, MI, MN, NY, PA, TN,
VA

EPA ’s 201 3 UIC Well Inventory (DCN
SGE0 1271 ) 201 3 16 CT, DE, GA, ID, MA, MD, ME, NC, NH, NJ, OR, RI, SC, VT, WA, WI
State oil and gas agency data Mostly 201 3
and more

recent 1 2 AK, AL, IL, KS, LA, MS, MO, MT, ND, NM,

TX , OK

Published r eports a Mostly 2012 1 1 AR, CA, CO, IN, NE, NV, OH, SD, UT, WV,
WY
Source: Well Count Documentation tab in Attachment 1 (DCN SGE01187.A01)

a

— T he primary published report ERG used was Veil Environmental, LLC’s 2015 report for the Ground Water Protection Council (GWPC) titled U.S. Produced Water Volumes and Management Practices in 2012 (DCN SGE01128), which contain s summaries of 2012 disposal well data for all oil and gas producing states. 3

As shown in Table 1 , the years associated with available active disposal well count data ranged from 201 2 to 2014. 4 However, approximately 90 p ercent 5 of the active disposal wells
ERG identified are based on 2012 and 2013 data. A lthough EPA proposed pretreatment standards for the Oil and Gas Extr action Category (40 CFR Part 435) on April 7, 2015 (80 FR 18557)

, ERG did not update the active disposal well counts using more up

- to

- date state databases (i.e., 2015 data). This is because the most recent injection volume available (discussed
in Section 2.2 ) represents 2012 data. Updating to more recent well counts would create a large difference between the count of active disposal wells and typical disposal rate p resented in Table

D

- 2. The following two subsections describe how ERG identi fied active disposal wells in state oil and gas databases and on tribal lands.

3 Veil Environmental, LLC’s 2015 report (DCN SGE01128) and the other available literature used for this analysis use the same definition of the term “oil and gas produced water” as is listed in this memoran dum, where oil and gas produced water includes both flowback and long

- term produced water. The report relied on state oil and gas agencies to estimate state level disposal well counts and volumes.

4 A snap shot of active disposal well counts was obtained fo r individual states. Therefore, the data year for each state varied depending on the availability of data.

5 ERG identified a total of 26,400 active disposal wells and 23,597 of them are based on 2012 or 2013 data (see the Summary of Results tab in Attachment 1 (DCN SGE01187.A01) ).Analysis of Active Underground Injection for Disposal Wells Memorandum

June 7 , 2016 Page 5

2.1.1 Accessing Databases

When accessing state and EPA OGWDW ’s database (DCN SGE010 12) t o determine the

num ber of active Class II disposal wells, ERG applied filters to the appropriate data fields in
order to exclude inactive wells and wells that are not designated as disposal Class II wells

. For each well record, the databases contain fields such as API #, longitude, latitude, well status (e.g., active, plugged, shut in), and well type (e.g., oil, gas, enhanced recovery, disposal). The two primary data fields ERG used were well status and well type. ERG documented the specific
filters a pplied for each state dataset within the Well Count Documentation tab. ERG included
C lass II disposal wells that were active or under construction

. Specific acronyms for well status and type vary by state. ERG chose the necessary filters that represent the desired category of wells (i.e., active Class II disposal wells) based on the data dictionary for the state database, where available. Otherwise, ERG used engineering judgment to determine the appropriate filters. When available, ERG referenced data dicti onaries published by state agencies to verify the appropriate filters. ERG specifically excluded inactive

, plugged, permitted, proposed, temporarily abandoned, and/or Class II enhanced recovery or hydrocarbon storage wells

.

2.1.2 Active Disposal Wells on Tribal Lands

ERG excluded wells on tribal lands reported by EPA OGWDW (DC N SGE01012) from the Summary of Results tab in Attachment 1 (DCN SGE01187.A01) because it was unclear if the
state database s already contained them. Although EPA has primary enforcement authority for wells on all tribal lands except the Navajo Nation and Ft. Peck Reservation, it appears that some states may have included tribal wells in their datasets as well. For example, the state databases
for New M exico (DCN SGE00 399 ), Wyoming (DCN SGE00 405; DCN SGSE00406 ), and Utah (DCN SGE00 403) 6 contain fields such as “ Land Type” that are populated with “ Indian ” or “Tribal ” for some wells. ERG summarized the number of active disposal wells on tribal lands
separat ely in the Tribal Disposal Wells tab in Attachment 1 (DCN SGE01187.A01)

. ERG did not identify references that contain injection volume into disposal wells on tribal lands

.

2.2 Average Disposal Rate per Well (gpd/well)

The Disposal Rate Documentation tab in Attachment 1 (DCN SGE01187 .A 0 1)
documents how ERG calculated average disposal rates per well on a state

- by

- state basis

. For each state, this tab includes the available disposal volume or rate data, the primary reference for the data (see column B, “Age ncy/Organization”; column C, “DCN for Volume Data”; and column D, “ Type of Data Source ”) , the date that the reference was accessed and last updated,
and how ERG estimated the average disposal rate per well using the data for this analysis

.

ERG used the fol lowing procedure . S ee the Disposal Rate Documentation tab in Attachment 1 ( DCN SGE01187 .A 0 1 ) for state

- specific methodology.

1. First, ERG identified total annual volumes (barrels , bbl ) 7 of produced water sent

to disposal wells and the number of active disposal wells for the same data year in
each state

. Table 2 lists the four types of data sources ERG used to identify the

6 ERG referenced Veil Environmental, LLC’s 2015 report for active disposal well counts for Wyoming and Utah. The underlying data used in Veil Environmental, LLC’s 2015 report are from the state oil and gas databases.

7 The oil and gas industry typically reports volumes in barrels (bbl), where 1 barrel is equivalent to 42 gallons.Analysis of Active Underground Injection for Disposal Wells Memorandum

June 7 , 2016 Page 6

total annual volume s of produced water sent to disposal wells . As shown in the

table, all of the available data were either from 2012 or 2013

.

2. For each state, ERG calculated the aver age disposal rate per well by dividing the
total annu a l volume (barrels) by 365 days/year and by the number of disposal
wells active in the same year . ERG then multipl ied by a conversion factor of 42 (gallons/barrel) to obtain the average disposal rate (gpd/well)

. The result is based on historical injection volume data 8 and is not related to the p ermitted or operational capacity of the well. 9

Table 2 . Summary of Data Sources Used for Disposal Rate Data

Type of Data Source Data Year for
Active Well
Count Number of

States States
Veil Environmental, LLC’s 2015 report titled U.S. Produced Water Volumes and Management
Practices in 2012 (DCN SGE01128) a 2012 23 AL, AR, CA, CO, FL, IN, KS, KY, LA, MI, MO, MS, MT, ND, NE, NV, NY, OH, SD, TX, UT, WV, WY

Communication with EPA Region 3 2013 2 PA, VA
State oil and gas agency data 2012 or 2013 3 AK, NM, OK
No active disposal wells 2013 5 AZ, MD, MN, NC, TN

No data available N/A 1 I L
Source: Disposal Rate Documentation tab in Attachment 1 (DCN SGE01187.A01)

a

— This report provides the total volume of oil and gas produced water sent to a specified number of active disposal
wells in 2012. 10

2.3 State Disposal Rate (MGD)

To provide context about how the availability of injection for disposal varies between regions with UOG extraction 11

, for each state, ERG calculated the state disposal rate (MGD) using Equation 1

.

Equation 1

State Disposal Rate ( MGD ) = N ( wells ) × DR avg ( gpd well )

1

, 000

, 000 gallo ns

MG

8 Typical average injection rates may vary for commercial and operator (private) Class II disposal wells, both of
which are included in the well c ounts and injection volumes used to calculate the average disposal rate.

9 Capacity is a function of the salinity of the injected fluid, injection pressure permit limit (if applicable), and/or injection rate permit limit (if applicable ) (DCN SGE00279).

10 V eil Environmental, LLC’s 2015 report (DCN SGE01128) and the other available literature used for this analysis use the same definition of the term “oil and gas produced water” as is listed in this memorandum, where oil and gas produced water includes both f lowback and long

- term produced water. The report also relied on state oil and gas agencies to estimate state level disposal well counts and volumes.

11 See Section D.2.3 in the TDD for more information about how the availability of Class II disposal wells a ffects the management of UOG extraction wastewater.Analysis of Active Underground Injection for Disposal Wells Memorandum

June 7 , 2016 Page 7

Where,

N = N umber of active disposal wells identified using methodology in Section 2.1

DR avg = Average disposal rate per well (gpd/well) using methodology in S ection 2.2

The Summary of Results tab in Attachment 1 (DCN SGE01187 .A 0 1) contains this
calculation. As explained in Sections 2.1 and 2.2

, respectively, the active disposal well counts and disposal rates per well are both pri marily based on 201 2 or 2013 data. ERG used the most

up

- to

- date data possible to estimate the state disposal rates (MGD) in Ta ble D

- 2 of the TDD

.

3.0 S UMMARY OF R ESULTS

For each state, t he Summary of Results tab in Attachment 1 ( DCN SGE01187 .A 0 1)
contains the number of active disposal well counts, average disposal rate per well (gpd/well), and state disposal rate (MGD) . This tab contains all of the data presented in Table D

- 2 in the TDD.
ERG excluded wells on tribal lands reported by EPA OGWDW (DCN SGE01012) from the Summary of Results tab in Attachment 1 (DCN SGE01187.A01) because it was unclear if the
state database s already con tained them. Instead , ERG summarized the number of active disposal wells on tribal lands separately in the Tribal Disposal Wells tab in Attachment 1 (DCN SGE01187.A01). This tab contains all of the data presented in Table D

- 3 in the TDD. No average disposa l rate per well (gpd/well) or state disposal rate (MGD) data was available for
wells on tribal lands.

The Summary of Results tab presents the results by state sorted by geographic region s as assigned in the EIA Annual Energy Outlook report (DCN SGE0 1192 ). However , Texas and New Mexico are both split into two different geographical regions (i.e., Gulf Coast and Southwest) by
EIA. Because ERG presents the results by state, ERG combine d the EIA “ Gulf Coast ” and

“ Southwest ” regions into one category for this an alysis to keep state data for Texas and New Mexico together

. For each region, ERG sorted the states by highest to lowest state disposal rate (MGD). Because ERG used different source s for active disposal well counts and average disposal rates, some states w ith active disposal wells have disposal rate data gaps

. ERG sorted
these states by highest to lowest count of acti v e disposal well counts.

4.0 D ATA Q UALITY AND A SSUMPTIONS

When assessing well database s for disposal well data, ERG did not substantiate
individu al well records within the underlying databases (e.g., well

- by

- well review). However,
ERG did compare results of active number of disposal wells and injection volumes from this analysis to the references listed below and confirmed that they generally agree. As such, the datasets are considered sufficiently accurate to observe trends at the state, regional, and national
levels.

 Veil Environmental , LLC ’s 2015 report for the Ground Water Protection Council

(GWPC) titled U.S. Produced Water Volumes and Man agement Practices in 2012 (DCN SGE01128 )

 University of Oklahoma’s 2014 technical presentation: Class II Underground Injection Control Well Data for 2010

– 2013 by Geologic Zones of Completion,
Oklahoma ( DCN SGE01089)Analysis of Active Underground Injection for Disposal Wells Memorandum

June 7 , 2016 Page 8

 Test data from states working towards e

- r eporting in EPA’s OGWDW’s National

UIC Database (not publicly available ) 12

When referencing published reports for disposal well data, ERG was unable to substantiate individual well records because the published reports only contained summary
statistics (e .g., total active disposal wells). However, ERG compare d the number of active disposal wells and injection volumes from published reports to the references listed below and confirmed that they generally agree. For several states, ERG identified published r eport data that estimated a greater number of active disposal wells , which is potentially due to the inclusion of inactive or temporary abandoned wells in these published reports

. For these states, ERG used the slightly more outdated reference instead of t he published report data in an effort not to overestimate the number of active disposal wells. ERG id entified these states in the Comments field in the Well Count Documentation tab in Attachment 1 (DCN SGE01187.A01)

.

 Corresponding state oil and gas databases

 Test data from states working towards e

- reporting in EPA’s OGWDW’ s National UIC Database (not publicly available )

As described in Section 2.0 and in the bullet points below , several assumptions were necessary to complete this analysis. These assumptions may increase or decrease the values presented in the TDD Table D

- 2 and are described below. As such, the results from this analysis
should be used with careful consideration of their strengths and limitations

.

 Calculation of the average disposal rate per wel l (gpd/well) : ERG included all wells identified as active even if some of these wells reported zero injection volume. This assumption may decrease the average disposal rate per well but only affects states where ERG used state databases as the source for injection volumes (NM, AK

, and OK ). However, ERG excluded wells that were identified as just being drilled because they could not have inj ected any wastewater.

 Calculation of the state disposal rate (MGD) : ERG included the number of disposal wells identified as currently being drilled (e.g., under construction) in the active number of disposal wells. This assumption may increase the current state injection rates but was intended to capture wells that will inevitably come online in the near future. However, ERG excluded wells from all calculations that were only permitted or proposed new well projects because these wells may be terminated even after they are permitted or proposed (i.e., may never come online)

.

 Missing v olume d ata : ERG was unable to identify injected volumes for Illinois
which has a substantial number of active disposal wells. Therefore, t he total volume of produc ed water injected into disposal wells in the nation estimated by this analysis may be an underestimate. Illinois is highlighted red in the Summary

12 EPA OGWDW is moving towards using an electronic reporting system for state primacy agencies, but it is not complete. A number of states have submitted some amount of data as they work to develop data flow, but most states with data are not final and there is a rang e of data quality. As there are known to be data gaps and the data is not approved by the state, it is not in the public record and is not used for official analyses.Analysis of Active Underground Injection for Disposal Wells Memorandum

June 7 , 2016 Page 9

of Results tab in Attachment 1 (DCN SGE01187 .A 0 1). Also, there is no available

injection volume data for well s on tribal lands.

 Number of active disposal wells : As explained in Section 2.1 , EPA OGWDW reported approximately 900 active disposal wells on tribal lands in the nation all
of which ERG summarized separately from wells reported by state agencies
because it was unclear if the state databases also contained these wells for some

states

.

5.0 Q UALITY C ONTROL P ROCEDURES

All of the analyses presented in this memorandum adhered to the Environmental Engineering Support for Clean Water Regulations Programmatic Quality Assurance Project Plan (PQAPP) (DCN SGE00957) and the Unconventional Oil and Gas (UOG) Supplemental Quality Assurance Project Plan (SQAPP) (DCN SGE00 958 ), inc luding collecting, evaluating, and analyzing existing data and information about underground injection disposal well s.

Specifically, ERG used the procedures described in Section 4 of the PQAPP to gather and manage existing data in support of the UOG rulema king. ERG staff entered reference
information for relevant sources into the UOG Literature Review database. The ERG index keeper reviewed all reference information, assigned each reference a Document Control Number (DCN ), imported the reference information into the UOG Project File Index database, and saved referenced files in the Electronic Project File folder.

ERG also used the procedures described in Section 3 of the SQAPP when collecting existing data for use in the UOG rulemaking. ERG used a combinatio n of sources, including reports, papers, and online databases from state regulatory agencies such as departments of environmental protection and oil and gas commissions. ERG assigned all references used in these analyses with one of the following s ource fl ag s ( DCN SGE00 958 ) :

 Source Flag A

– Journal articles and documents prepared by or for a government agency (e.g., site visit reports, industry meeting notes);

 Source Flag B

– Documents prepared by a verified 13 source that include citation information (e.g., operator reports, vendor documents, university publications);

 Source Flag C

– Documents prepared by a verified source that do not include citation information (e.g., operator reports, vendor documents, conference presentations); and

 Source Flag D

– Docu ments prepared by a source that could not be verified and
that do not include citation information.

ERG followed the procedures described in Section 7.0 of the PQAPP to generate, evaluate, and analyze data using a spreadsheet. ERG conducted the following QA checks during the analyses:

13 ERG considered sources as “verified” if we were able to find information about the auth or outside of the reference document. ERG primarily verified information by looking for company/organization websites that confirmed the author’s affiliation with the UOG industry.Analysis of Active Underground Injection for Disposal Wells Memorandum

June 7 , 2016 Page 10

 ERG created the Injection for Disposal Well Data spreadsheet provided in
Attachment 1 ( DCN SGE01187 .A 0 1 ) to track relevant data and to document analyses. ERG performed a 100 percent check of all data entry, manipulations and calculations, and documented these in the internal version of the spreadsheet.

 For all analys e s performed in state specific Access databases, one team member created queries and another team member reviewed the design and logic of the queries. ERG document ed these checks in the internal version of the Injection for Disposal Well Data spreadsheet provided in Attachment 1 ( DCN
SGE01187 .A 0 1 )

.

 ERG had a senior staff member familiar with ELGs and the UOG rulemaking
review the results from the Injection for Dispo sal Well Data spreadsheet provided
in Attachment 1 ( DCN SGE01187 .A 0 1 ).

6.0 R EFERENCES

Table 3 provides citations for references used in the s e analyses and their assigned source flag.

Table 3 . References

DCN State Full Citation Source Flag a

SGE00132 Multiple U.S. EPA. 2011. Underground Injection Control Program: Class II
Wells

— Oil and Gas Related Injection Wells (Class II). Available online

at: https://www.epa.gov/uic/class

- ii

- oil

- and

- gas

- related

- injection

- wells A

SGE0 12 71 Multiple US EPA. 2015. UIC Inventory by State in 2013. Office of Water. Office of Ground Water and Drinking Water. Underground Injection Control. A

SGE00276 N/A US EPA. 2012. Meeting with XTO Energy, Inc. about Unconventional
Oil and Gas Sanitized. A

SGE00279 Multiple U.S. EPA. 2012. Meeting Summary: Conference Call with North Star Disposal, Inc. Regarding Underground Injection Operations in Ohio. (July 2). A

SGE00383 KS Kansas Geological Survey (KGS). 2012. Kansas Wells. Downloaded on
12/21/2012. Available online at: http://www.kgs.ku.edu/PRS/Ora_Archive/ks_wells.zip

. A

SGE00384 KS Kansas Geological Survey (KGS). 2004. Oil and Gas Well Database
Abbreviations. Downloaded on 2/4/2013. Available online at: http://www.kgs.ku.edu/Magellan/Elog/status.html

. A

SGE00385 LA Louisiana Department of Natural Resources (LADNR). 2012. Produced Fluid Disposal Wells By Field. Office of Conservation. Downloaded on
12/21/2012. Available online at: http://repo rts.dnr.state.la.us/reports/rwservlet?SRCN4282J_p

. A

SGE00386 LA Louisiana Department of Natural Resources (LADNR). 2012. UIC Well Class Type. Office of Conservation. Downloaded on 12/21/2012.
Available online at: http://sonris.com/

. A

SGE00387 LA Louisiana Department of Natural Resources (LADNR). 2012. Status Code Description. Office of Conservation. Downloaded on 12/21/2012.
Available online at: http://sonris.com/

. AAnalysis of Active Underground Injection for Disposal Wells Memorandum

June 7 , 2016 Page 11

Table 3 . References

DCN State Full Citation Source Flag a

SGE00388 MO Missouri Department of Natural Resources (MODNR). 2012. Oil and Gas Permits. (December 19). Accessed on 12/21/2012. A

SGE00389 MT Montana Board of Oil and Gas Conservation (MTBOGC). 2012. UIC
Wells. Accessed on 12/21/2012. A

SGE00391 ND North Dakota Industrial Commission (NDIC). 2013. Well Type Definitions. Department of Mineral Resources, Oil and Gas Division.
Last Accessed on 2/4/2013. Available online at: https://www.dmr.nd.gov/oilgas/code help.Asp

. A

SGE00392 ND North Dakota Industrial Commission (NDIC). 2013. Well Status Definitions. Department of Mineral Resources, Oil and Gas Division.
Last Accessed on 2/4/2013. Available online at: https://www.dmr.nd.gov/oilgas/codehelp.Asp

. A

SGE00399 NM Petroleum Recovery Research Center (PRRC). 2012. All Wells Database.
Downloaded on 2/4/2012. Available online at: http://octane.nmt.edu/gotech/Petroleum_Data/allwells.Aspx

. A

SGE00402 TX Texas Railroad Commission (TXRCC). 2012. Injection & Disposal Query Criteria. Accessed on 5/28/2013. Available online at: http://webapps2.rrc.state.tx.us/EWA/uicQueryAction.do

. A

SGE00403 UT Utah Department of Natural Resources (UTDNR). 2012. Well
Information Search. Accessed on 2/4/2013. Available online at: http://oilgas.ogm.utah.gov/Data_Center/LiveData_Search/well_data_look up.cfm

. A

SGE00405 WY Wyoming Oil and Gas Commission (WOGC). 2012. Well Header Data
111412. Downloaded on 12/19/2012. Available online at: http://wogcc.state.wy.us/urecordsMenu.cfm?Skip= ’ Y ’ &oops= #oops#

. A

SGE00406 WY Wyoming Oil and Gas Commission (WOGC). 2013. Codes for Well
Files. Downloaded on 2/4/2013. Available online at: http://wogcc.state.wy.us/codes.html

. A

SGE00526 AL Geological Survey of Alabama

– State Oil and Gas Board (AL OGB).
2013. Well Records Database. Accessed on 6/4/2013. A

SGE00537 CA Horsley Witten Group. 2011. California Class II Underground Injection Control Program Review. A

SGE00551 MS Mississippi Oil and Gas Board (MSOGB). 2013. Well Information Report Search. Accessed on 6/4/2013. A

SGE00557 ND North Dakota Industrial Commission (NDIC). 2014. Basic Subscription
Services

– Well Index. Department of Mineral Resources, Oil and Gas
Division. Last Accessed on 1 / 27 /2014. A

SGE00613 N/A U.S. Environmental Protection Agency (U.S. EPA). 2013. Meeting with industry representatives about the unconventional oil and gas effluent guid eline rulemaking. (February 28). A

SGE00623 N/A U.S. Government Accountability Office (GAO). 2012. Energy

- Water

Nexus. Information on the Quantity, Quality, and Management of Water Produced During Oil and Gas Production. (January). GAO

- 12

- 156. A

SGE00625 N/A US EPA. 201 5 . Site Visit Report Southwestern Energy Fayetteville Shale Operations. Sanitized. A

SGE00635 N/A US EPA. 2012. Site Visit Report Chesapeake Energy Corporation Marcellus Shale Gas Operations Sanitized. AAnalysis of Active Underground Injection for Disposal Wells Memorandum

June 7 , 2016 Page 12

Table 3 . References

DCN State Full Citation Source Flag a

SGE00770 IL Shutt, Doug. 2014. Email Correspondence between IL Office of Oil and Gas Resource Management and EPA. (May 30). A

SGE00957 NA Eastern Research Group, Inc. 2013. Environmental Engineering Support for Clean Water Regulations Programmatic Quality Assurance Project
Plan (PQAPP)

. October 1

. A

SGE00958 NA Eastern Research Group, Inc. 2014. Unconventional Oil and Gas (UOG) Supplemental Quality Assurance Project Plan (SQAPP)

. August 15. A

SGE00959 AK Alaska Oil and Gas Conservation Commission. 2014. AOGCC Data Extract Zip File

. (April 8). A

SGE00960 AK Alaska Oil and Gas Conservation Commission. 2014. AOGCC Data Extract Zip File Table Description

. (April 8). A

SGE01012 Multiple U.S. EPA. 2014

. Class II Disposal Inventory in EPA Direct Implementation Programs . Data as of 3/31/2014. A

SGE01014 OK Oklahoma Corporation Commission (OCC). 201 5 . UIC Injection
Volumes 201 2. Downloaded on 2/5 /201 5 . Available online at: http://www.occeweb.com/og/ogdatafiles2.htm

. A

SGE01015 OK Oklahoma Corporation Commission (OCC). 2014. Well_Status.
Downloaded on 12/18/2014. Available online at: http://www.occeweb.com/og/ogdatafiles2.htm

. A

SGE01089 OK Murray, Kyle. 2014. Class II Underground Injection Control Well Data
for 2010

– 2013 by Geologic Zones of Completion, Oklahoma. Oklahoma Geological Survey Open

- File Report (OF1

- 2014). Norman, OK. Pp. 32. A

SGE01109 PA/VA U.S. EPA. 2015. PA and VA Class II Injection for Dispos al Volume

Data. A

SGE01128 Multiple Veil, John. 2015. U.S. Produced Water Volumes and Management
Practices in 2012. Veil Environmental, LLC. Prepared for Ground Water Protection Council (GWPC). A

SGE01179 N/A ERG. 2016. Data Compilation Memorandum for the Technical Development Document (TDD). A

SGE01188 N/A U.S. EPA. 2016. Technical Development Document for Proposed
Effluent Limitations Guidelines and Standards for Oil and Gas
Extraction. A

SGE01192 All U.S. Energy Information Administration. 2015. Annual Energy Outlook 2015 with Projections to 2040. DOE/EIA

- 0383(2015). (April). A

SGE01334 N/A ERG. 2016. Memorandum Providing a Crosswalk between Tables and Figures in the Proposed and Final Technical Development Document for
Effluent Limitations Guidelines and Standards for Oil and Gas
Extraction

. A

a

— Source Flag A

— J ournal articles and documents prepared by or for a government agency (e.g., site visit reports, industry meeting notes). Source Flag B

— Documents prepared by a verified source that include citation information (e.g., operator reports, vendor documents, university publications). Source Flag C

— Documents prepared by a verified source that do not include citation information (e.g., operator reports, vendor documents, conference presentat ions). Source Flag D

— Documents prepared by a source that could not be verified and that do not include citation
information.Analysis of Active Underground Injection for Disposal Wells Memorandum

June 7 , 2016 Page 13

A TTACHMENT 1 :

A NALYSIS E XCEL F ILE ( DCN SGE01187 .A 0 1)